Fluid-operated motor

ABSTRACT

A source of pressurized fluid is constantly introduced into one end of a cylinder having a double acting reciprocating piston assembly mounted therein. A valve assembly including piston elements is slidably secured to the main piston assembly for displacement relative to the cylinder and piston assembly for controlling the application of fluid pressure to opposite ends of the piston assembly alternately.

United States Patent [56] References Cited UNITED STATES PATENTS [72] inventor George E. Doughton Tobaccoville, N.C.

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ABSTRACT: A source of pressurized fluid is constantly introduced into one end of a cylinder having a double acting reciprocating piston assembly mounted therein. A valve assembly including piston elements is slidably secured to the main piston assembly for displacement relative to the cylinder and piston assembly for controlling the application of fluid pressure to opposite ends of the piston assembly alternately.

a 1 4 2 9 231/2 Al 73 5 l lbiu l 2 3 M. m m m "9 m5 m U 2 n "H a m m m h a U C U n M L i 0 m x m I. U .m F U H m 5 5 5 FLUID-OPERATED MOTOR BRIEF SUMMARY OF THE INVENTION The present invention relates to a fluid-operated motor adapted to be incorporated in or associated with devices or equipment which require piston rod displacement to actuate or control movement of a machine element or mechanism.

Fluid motors provided with valve means for automatically reversing piston movement to control reciprocation are known, for example, as disclosed by applicants prior US. Pat. No. 2,851,013.

Briefly, this invention comprises an improved fluid operated motor having an automatically reciprocating piston assembly which is actuated by a fluid under a substantially uniform pressure. Fluid under pressure is continuously supplied to the upper end of a double action cylinder. Such pressure applied against the top of the piston assembly forces the assembly downwardly for a predetermined distance at which time a valve assembly is forced downwardly by the piston assembly and disengaged from the cylinder head plate thus permitting fluid to pass through openings in the piston assembly to the lower side of the assembly. Since the total surface area on the lower side of the piston assembly is greater than the top surface area, the piston assembly reverses and is forced upwardly. As the assembly reaches its topmost position, the value assembly, also being displaced upwardly, travels relative to the piston assembly permitting the fluid pressure acting upon the lower portion of the piston assembly to exhaust through vent passages and the valve assembly and the exhaust ports, thus permitting the reciprocation cycle to be repeated.

A primary object of the invention is to provide a fluid operated motor having an automatically reciprocated piston assembly which is actuated by fluid under uniform pressure.

Another object of the invention is to provide a fluid operated motor having an improved form of valve mechanism for automatically reversing the piston assembly.

A further object of the invention is a fluid motor having a double action piston assembly cooperable with a slidable valve assembly having selectively proportioned fluid contact surfaces for automatically reversing the piston assembly.

One feature of the invention is a fluid motor having the piston assembly and slidable valve mechanism completely enclosed within the cylinder.

Another feature of the present invention is to provide a fluid-operated motor of simple and inexpensive construction having a minimum number of parts.

Other objects and advantages will be readily apparent to those skilled in the art during the course of the following description of one embodiment of the present invention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES FIG. l is a side elevational view of a fluid motor embodying the present invention;

FIG. 2 is a fragmentary, cross-sectional, side elevational view of the fluid motor of FIG. 1, illustrating one position of motor operation;

FIG. 3 is a schematic, fragmentary side elevational view of the fluid motor, similar to FIG. 2, illustrating the movement of the motor components to a changed position;

FIG. 4 is a fragmentary side view of the fluid motor similar to FIG. 3, rotated approximately 90 to a horizontal position, and illustrating a third position of movement of the motor components;

FIG. 5 is a fragmentary, sectional side elevational view of the valve assembly and th piston assembly; and

FIG. 6 is a bottom plan view of the fluid motor of FIG. 1

DETAILED DESCRIPTION OF THE INVENTION 1 Referring to the drawing which illustrates a preferred embodiment of the present invention, there is illustrated a fluidoperated motor 10 that may be incorporated witl'numerous devices that require piston displacement for actuating various machine elements or meclanisms.

The fluid motor 10 comprises a cylinder 12 formed from a tubular sleeve 14 whiclis closed by headplate 116 at one end and by the base mounting plate 18 at the other end. The headplate 16 is provided with an inlet passageway 20 and a threaded hose adapter 22 for the introduction of a fluid medium from a pressure source, not shown, into the cylinder 12. While the actuating fluid described herein is compressed air, it is to be understood that other fluids, liquid or gaseous, may be employed for operating the fluid motor 10 with equally satisfactory results. The headplate 16 is provided with a central bore 24 and a recess 26 for receiving a sealing ring 28 to slidably guide one end of the tubular valve assembly 30 in the cylinder 12. A second bore 32 provided in the head plate 16 and of a diameter larger than the bore 24 communicates with bore 24 thus defining a shoulder 34. Threadably secured to a head plate 16 is a cap 36 provided with an elongated bore 38, for slidably receiving a portion of valve mechanism 30, and a plurality of exhaust ports 40. A washer 42 located inter mediate cap 36 and headplate l6 maintains the sealing ring 28 within recess 26.

The base mounting plate 18 has a recess 44 provided within the lower portion for threadably receiving a bushing 46. An upwardly opening recess 48 for receiving the nut 50 of the piston assembly 52 communicates with recess 44 through the bore 54. Apertured nut 56, threadably secured to the bushing 46, maintains the fluid motor 10in assembled relation upon a support frame or machine element with which the fluid motor is to be associated.

Suitable fastening means, such as the bolts 58, secure the head plate 16, base plate 18 and tubular sleeve 14 together as a unit to form the enclosed piston assembly cylinder 12. Ring gaskets 60,60 are positioned within radial slots 62, 64 of the headplate and base plate, respectively, adjacent the edges of sleeve 14 to seal the cylinder 12 against leakage. A flat circular stop plate 66, having a central bore 68 therein, is fixedly secured by suitable fasteners 70 intermediate the length of the tubular sleeve 14. The stop plate 66 divides the cylinder 12 into two chambers 72, 74 and serves as a stop or shoulder to limit the movement of piston assembly 52. Sealing rings 76, 78 are provided within radial slots and stop plate 66 to act as a seal between chambers 72, 74 of cylinder 12.

Located within cylinder 12 is a double action, reciprocating piston assembly 52 comprising a rod 80, slidably mounted within the bushing 46, and bore 54 of base plate 18, and through the apertured'nut 56. Fixedly positioned on the upper end of rod 80 and threadably receiving one end portion of a tube 82 is a nut 50. Concentrically mounted about tube 82 and maintained in spaced relation thereto is a sleeve 84. Supported at the opposed ends of concentrically mounted tube 82 in sleeve 84 are main pistons 86, 88, each piston being provided with sealing rings 90, 92. The: sealing rings 92 are located within radial grooves around the pistons and slidably engage the inner wall of the tubular sleeve 14 upon displacement of the piston assembly 52. Sealing rings are located within radial grooves formed concomitantly with bores 94, 96 passing through pistons 88, 86, respectively. The sealing ring 90 on piston 88 engages the outer periphery of tube 82 while the sealing ring 90 on piston 86 engages the outer periphery of the sleeve 84. The sleeve abuts against one face of piston 88 and is received within and supported upon a shoulder portion 98 formed by a reduced diameter bore 99 passing through piston 86. Each end of the tube 82 is threaded, as more clearly shown in FIG. 5, and cooperates with nuts 50 and 100 and sleeve 84 for supporting pistons 86, 88 in spaced relation and for maintaining the pistons, tube and sleeve in assembled fixed relation relative to each other. The air space or chamber 102 between the concentrically mounted tube and sleeve provides a means for communicating with the opposite sides of each of pistons 86, 88 within chambers 72, 74 of cylinder 12.

A tubular valve mechanism 30 comprises a first portion 104 positioned for sliding movement within bores 38 and 24, a

reduced diameter portion 106, a portion 107, piston member 108, piston member 110, and an end portion 112. It is to be noted that the surface area 125 of piston member 108 is greater than the surface area 126 of member 110. The piston member 110 is received with tube 82 and sealing ring 114 slidably engages the inner wall of tube 82 upon reciprocating movement of the valve 30. Piston member 108, having sealing ring 116 positioned thereon, is adapted for movement between a position located within chamber 72, as shown by FIG. 4, to a position within bore 32 of headplate 16, as illustrated by FIG. 2. As most clearly shown by FIG. 2, nuts 50 and 100 are provided with a series of radial slots 120, 118, respectively, sleeve 84 is provided with a series of radially directed slots 122 located at one end thereof adjacent piston 88, and tube 82 is provided with a plurality of radially directed openings 124. Reciprocating movement of valve assembly 30 between the extreme positions thereof is limited by nut 100 which is threadably secured into tube 82. It is to be noted that the valve assembly 30 is capable of being slidably actuated within piston assembly 52 permitting limited movement from the position of FIG. 2 within piston 108 adjacent to nut 100, to the position of FIG. 3 wherein the nut 100 engages piston member 110. The radial slots 118 in nut 100 permits the passage of fluid from the portion of chamber 72 on the upper end of piston 88, through the slots 118, axially through the nut 100 and into the chamber 128 formed between the stem portion 107, the interior of tube 82 and piston member 110. Depending upon the relative position of piston member 110 with respect to the tube 82, it is possible for the fluid to pass through openings 124 and into space 102 defined by tube 82 in sleeve 84. Radial slots 122 in sleeve 84 and slots 120 in nut 50 permit passage of fluid between air space 102 and chambers the lower portions of 72 and 74, respectively. The fluid is directed through bore 99 formed in piston 86 which is of greater diameter than tube 82 as most clearly shown by FIG. 2.

To this point the various elements of the fluid motor have been described specifically with reference to construction details. Now the operation of the fluid motor will be described. Compressed air, or other fluids or gasses 10, is introduced into the inlet passageway 20 in the head plate 16. Assuming that the various elements and components of the motor 10 to be initially positioned as illustrated in FIGS. 2 and 5, pressure will build up almost instantaneously in the passageway 20 and within the upper portion of chamber 72 against the top side of piston 88 to force the entire piston assembly 52 in a downward direction within chamber 72. As the piston assembly 52 moves downwardly in the cylinder 12, any fluid pressure that may be on the bottom side of pistons 86, 88 is relieved through slots 120, 122 and through axial passageway 130 of valve assembly 30 when the latter is in an upward position. It will be noted that fluid pressure cannot at this time exhaust through bores 32, 38 and ports 40 since the piston member 108 is positioned within bore 32. Upon downward movement of piston 88 and consequently the entire piston assembly 52, consisting of tube 82, sleeve 84, piston 86, nuts 50, 100 and piston rod 80, as indicated by the arrows of FIG. 3, it will be seen that after a predetermined amount of movement nut 100 will engage piston member 110 of valve assembly 30 whichup until this time has remained in a stationary position, as shown by FIGS. 2 and 5. Valve assembly 30 has remained stationary since the surface area 125 of valve 108, being acted upon by fluid within the upper portion chamber 72 passing through radial slots 118 and into chamber 128, FIG. 5, formed between the outer diameter of stem portion 107 and the inner diameter of tube 82. Further movement of piston assembly 52 in a downward direction will cause movement of valve assembly 30 downwardly since nut 100 has en gaged piston member 110. Subsequently, piston member 108 is removed from bore 32 and forced downwardly to the position illustrated by FIG. 4 due to the fluid pressure within the upper portion of chamber 72 acting upon the tapered portion 130 of piston member 108 and the pressure within air space 128 acting upon surface area 126 of piston member 110. In the position of FIG. 4, the valve assembly portion 104 is positioned within bore 24, and sealing ring 28 prevents leakage of fluid pressure from the upper portion of chamber 72.

Once the valve assembly is moved to the FIG. 4 position, it it to be noted that piston member is moved below, or to the left of, radial openings 124 in tube 82 thus permitting fluid to flow from the upper portion of chamber 72, through slots 1 l8, chamber 128, openings 124 in tube 82 and into the space 102 provided between the concentrically spaced tube and sleeve. The fluid then passes through radial slots 122 provided in sleeve 84 immediately below piston 88, and through radial slots provided in nut 50 immediately below piston 86 and consequently intothe lower portion of each of chambers 72 and 74. The total exposed surface area of the bottom side of pistons 86, 88 is approximately twice the top surface area of piston 88. Thus as the compressed fluid builds up substantially instantaneously and simultaneously in the lower portions of chamber 72, 74 below pistons 86, 88, the piston assembly 52 is forced upwardly. As soon as the reversing action occurs the valve assembly 30 begins movement to the right, as shown by FIG. 4, due to the engagement of nut 100 of piston assembly 52 with piston member 108 of valve assembly 30. The piston assembly 52 is moved to the position illustrated by FIG. 2 by the force applied to the lowerside of both pistons which overcomes the force applied to the top side of piston 88. Once the valve assembly 30 is moved sufficiently by piston assembly 52 such that the valve member 108 begins to move within bore 32, the fluid pressure in the upper portion of chamber 72 acting upon surface area forces the valve member completely within the bore as shown by FIGS. 2, 3. Reduced diameter portion 106 of valve mechanism 30 permits fluid trapped in bore 32 to exit through bores 24 and 38 as piston member 108 is forced into the bore 32. When the piston assembly 52 reaches its limit of travel on the upstroke, just as piston member 108 begins to enter bore 32, it will be seen that the pressure acting upon surface area 125 moves the valve assembly 30 upwardly slidably displacing piston member 110 within tube 82 from the left side of tube openings 124, as shown by FIG. 4, to the right side thereof. This permits the fluid pressure to flow from the lower portions of chambers 72, 74 below pistons 86, 88, through radial openings 122, 120 in the sleeve and nut 50, respectively, into chamber 102 between the sleeve and tube, through openings 124 and the tube, into passageway of valve assembly 30 and exhaust through ports 40. At the time fluid is exhausting from the lower portion of chambers 72, 74, fluid pressure continuously being supplied into the upper portion of chamber 72 begins forcing piston assembly 52 downwardly, thus permitting another reciprocating cycle of movement to be repeated as heretofore described.

I claim 1. A fluid-operated motor comprising an enclosed cylinder, a double action piston assembly mounted for reciprocating movement within said cylinder, said cylinder having an end portion with an inlet passageway for introducing pressure fluid continuously to one side of said piston assembly, and a valve assembly completely enclosed within said cylinder comprising a first portion slideably retained by said end portion and a second portion attached to said first portion for movement therewith and slideably retained within said piston assembly for displacement relative to said cylinder and said piston assembly for automatically controlling the application of fluid pressure to opposite sides of said piston assembly for regulating the direction of displacement of said piston assembly, said piston assembly comprising a plurality of pistons axially spaced within said cylinder, and means maintaining said pistons in spaced relationship, said means maintaining said pistons in axially spaced relationship including hollow members having a series of selectively spaced openings for communicating with said valve assembly.

2. A fluid-operated motor as defined in claim 1, said valve assembly having relatively proportioned shoulder areas spaced axially to cooperate with the spaced openings on said hollow members and said end portion to control the reciprocation of the piston assembly upon admission of pressure fluid into said cylinder.

3. A fluid-operated motor as defined in claim 2, said valve assembly further including an axial passageway to vent fluid from the cylinder through said hollow member openings to the atmosphere.

4. A fluid-operated motor comprising an enclosed cylinder, a double action piston assembly mounted for reciprocating movement within said cylinder, said cylinder having an end portion within an inlet passageway for introducing pressure fluid continuously to one side of said piston assembly, and a valve assembly completely enclosed within said cylinder comprising a first portion slideably retained by said end portion and a second portion attached to said first portion for movement therewith and slideably retained within said piston assembly for displacement relative to said cylinder and said piston assembly for automatically controlling the application of fluid pressure to opposite sides of said piston assembly for regulating the direction of displacement of said piston assembly, said piston assembly including a piston, piston rod and means maintaining said piston and piston rod in axially spaced relation, said valve assembly being slideably received within said means, said valve assembly second portion comprising an enlarged shoulder area for communicating with said means, and said portion comprising an enlarged shoulder area cooperating with said end portion, said valve assembly further including an axial passageway extending through said first and second portions.

5. A fluid-operated motor as defined in claim 4, said means including concentrically spaced hollow members having openings therein providing fluid communication between said cylinder and said valve assembly. 

1. A fluid-operated motor comprising an enclosed cylinder, a double action piston assembly mounted for reciprocating movement within said cylinder, said cylinder having an end portion with an inlet passageway for introducing pressure fluid continuously to one side of said piston assembly, and a valve assembly completely enclosed within said cylinder comprising a first portion slideably retained by said end portion and a second portion attached to said first portion for movement therewith and slideably retained within said piston assembly for displacement relative to said cylinder and said piston assembly for automatically controlling the application of fluid pressure to opposite sides of said piston assembly for regulating the direction of displacement of said piston assembly, said piston assembly comprising a plurality of pistons axially spaced within said cylinder, and means maintaining said pistons in spaced relationship, said means maintaining said pistons in axially spaced relationship including hollow members having a series of selectively spaced openings for communicating with said valve assembly.
 2. A fluid-operated motor as defined in claim 1, said valve assembly having relatively proportioned shoulder areas spaced axially to cooperate with the spaced openings on said hollow members and said end portion to control the reciprocation of the piston assembly upon admission of pressure fluid into said cylinder.
 3. A fluid-operated motor as defined in claim 2, said valve assembly further including an axial passageway to vent fluid from the cylinder through said hollow member openings to the atmosphere.
 4. A fluid-operated motor comprising an enclosed cylinder, a double action piston assembly mounted for reciprocating movement within said cylinder, said cylinder having an end portion within an inlet passageway for introducing pressure fluid continuously to one side of said piston assembly, and a valve assembly completely enclosed within said cylinder comprising a first portion slideably retained by said end portion and a second portion attached to said first portion for movement therewith and slideably retained within said piston assembly for displacement relative to said cylinder and said piston assembly for automatically controlling the application of fluid pressure to opposite sides of said piston assembly for regulating the direction of displacement of said piston assembly, said piston assembly including a piston, piston rod and means maintaining said piston and piston rod in axially spaced relation, said valve assembly being slideably received within said means, said valve assembly second portion comprising an enlarged shoulder area for communicating with said means, and said portion comprising an enlarged shoulder area cooperating with said end portion, said valve assembly further including an axial passageway extending through said first and second portions.
 5. A fluid-operated motor as defined in claim 4, said means including concentrically spaced hollow members having openings therein providing fluid communication between said cylinder and said valve assembly. 